I have heard from Dr David Hunt that he is due shortly to produce his next issue of Huitzilopochtlia which will be pages 65 - 72 of the series, and I think edition 7.
As you will probably all know, Dr Hunt is the moving force behind the New Cactus Lexicon, and Cactaceae Systematics Initiative, but he hasn't forgotten his first area of work which of course in the genus Mammillaria. This is the focus of Huitzilopochtlia, and in the issues to date, he has covered a number of problematic species, and also related some of his early travels, and those of Dr Alfred Lau.
In this next issue, he plans to re-launch the survey
that Mark of this Forum started in 2009 , to see just how many of Lau's plants - any with a Lau field number - are still in existence.
Since that date, there have been many new members of the Forum, and from many other countries. I therefore urge you to sign up for Huitzilopochtlia simply by sending an email to David at firstname.lastname@example.org and you will be added to his distribution list. It is a free issue, as all have been, and is in pdf form, so readable on many platforms.
In the previous survey, the figures came to 121 out of 390 Lau collections were still around in collections of those who reported.